Xtransmission c control



Jan. 6, 1953 L. B. FORMAN TRANSMISSION CONTROL SYSTEM 755 y a a 73W 7 i Filed July 24, 1951 INVENTOR.

v oz/rs .5, forman if 70K/vins Patented Jan. 6, 1953 Louis B. Forman,

Chrysler Corporation,

.Detroit, Mich., assigner to Highland Park, Mich., a

`corporation of Delaware Application July 24, 1951,-Serial No. 238,302

(Cl. "i4-4t2) 1:2 Claims. l

This invention relates to motor vehiclesand refersvmore particularly to power transmissions and control systemstherefor.

My inventionhas particularlreference'totrans mission control :systems wherein the .disengagement of positively :engageable drivecontrol elements-is facilitated by relieving' the torque 'load on these elements'aslby momentary interruption ofthe engine ignitionsystem. Examples of" transmissions of this ch-aracter are described `inthe patents to Carl A. Neracher et al.`2,455,943..grant ed' December v1.4, r19:48, Hand. Augustin J .,'Syrovy etal. 2,490,604'granted December 6, V1949.

It has been customary, as shown by the .aforesaid patents,.to provide a shiftable drive-:control element of toothed character arrangeditointerengage with a second tootheddrive .control element after passing through a toothed @blocken Engagement occurs upon synchronismfobtaining between the drive control elements subsequent to engine deceleration by V'accelerator releasing. movement, and the. shiftable element .is Vadapted lto 'be unloaded, .as described above, to Ifacilitateitsdisengagementffromitscompanion drive control element.

f The `drive controlfelements are general-1.511sciarranged-in" thev transmission-that: uponsrelativefengagement under governor control Iat `or iabove. a predetermined vvehicle-speed, -there-lis provideda fast speed ratiodrive'through the transmission, usually a directdrivefand when 'relatively disengaged under. governor co trol below a :predeter- -mi-ned speed, 'or' by kickdown y means --such r' as accelerator `actuated switch means -overruling Vthe governor, there is provided another speed-ratio drive which *isV usually a slowerfspeed/ratio drive than thefirst mentioned one.

Also .customarily providedare prime mover or diierential lpressure, servo Vmotor means 'which may comprise a-spring anda hydraulic orvacuum operated'motor having amovable piston, `for controlling rshift of the shftabledrivecontrol element through aniassociated; shift railorlever. system. In the case of thehydraulic system, asztypilied by the Syrovy et al. patent.aforesaid,pressure fluid actingv upon the lpiston-,will .cause it to: compress a `disengaging yspringvandI an engaging spring, andbuild up sufficient kavailablefforce in 'the latter to move theshift rail andbyit the shiftable drive control elementfagainst' its blocker Iand then kinto .engagement with its :companion Vdriveucontrol element when synchr'onization of the. drive control kelements subsequently zoccurs. .In .the case l ofthe vacuum `power system, as typified bythe Neracheret al. patentvacuum is have ini general been'satisfactory,

utilized to cause the piston to compress a disengaging spring and through a rod extension of the piston, unload an engaging spring previously tensioned by operation of the rod, the latter spring in turn acting upon a lever to effect movement of the shiftableelement against its blocker and into subsequent engagement with its companion drivercontrol element whenthe'drive controlv elements obtain synchronism.

Transmission systems of the aforesaid typical character also usually include electromagnetically controlledpvalving for controlling venting l(zadrnissiongof atmospheric pressurelof the servo motorfand operation ofthe piston such that-when the motor is vented-the disengaging springactuates the piston to effect disengaging shift of the Vshiftable drive control element accompanied by ignition interruption, the latter occurringasan incidentv to available lost motion-operation of the pistonrelative to the shift rail in Syrovy-etal., andithe` piston rod relativeto the lever operating member in Neracher et al.

Customarily there'is also provided an ignition interruptergswitch operated `by movement of the piston :in Syrovy et al. or by the piston 4rod `in Nera-cher :et al. Moreover, as `in the above patents, there is provided an electrical system i-ntended to accommodate interruption of vthefen- .gine ignition Vonly during the disengaging stroke 'of .the piston, it being so arranged that even though `the V,ignition interruption switchv closesY von :theivreturn (engaging) stroke,the ignitionisfnot ordinarilyv grounded out because at such time neither 'of the parallel arranged kickdown and governor switches which are arranged in series with the'ignition interrupter switch and in series with'the valve solenoid inra parallel circuiting is closed. Hence iiring of the engine is not usually interrupted during acceleration from vehicle standstill in the lslowerspeed ratio drive.

Although the foregoing described arrangements they have been open itoone or morev unforeseen conditions of operationfwhich it, is desirable to avoid.

Furthermore, in the arrangement disclosed by Neracher et al. and Syrovy et al., especially Where ahigher resistor type of ignition harness hasl been employed, some lurching of the Vehicle has been noticeable in vehicle operation during upshifts. It is believed that in a circuiting wherein actuation of the interrupter switch places the ignitionprimary coil vand the solenoid of the control valve in parallel circuits, .the solenoid coil acts as a parallel impedance of 'low kvalue to the primary coil of the ignition and causes the spark delivered by the secondary at the plugs at the time of current flow thereto to be weakened. In this connection, it may be observed that under normal engine operation the higher the engine R. P. M., the lower is the secondary voltage, and since the upshift takes place at a substantial R. P. M. the effect of the low impedance is to weaken the spark sufficiently so that it may be unable to keep the engine running momentarily, as by causing the engine to misfire. This condition can occur, for example, in the Neracher et al. arrangement and in the Syrovy et al. system when the relay coil of the latter h-as a low impedance effect on the ignition primary.

An object of my invention is to provide an improved ignition interruption control adapted for use, for example, with a transmission control system of the types disclosed in the aforesaid patents and which is capable of operation without weakening the ignition during the return, i. e., upshift stroke of the piston.

- Another object of the invention is to provide a transmission shift control system having means for interrupting the engine ignition when effecting a downshift, but which system inhibits weakening of the ignition spark intensity during the upshifting operations.

Still another object is to provide a transmission control system including ignition interrupting means and speed responsive and accelerator controlled differential pressure fluid means for effecting shifts in the transmission wherein control circuiting is arranged to make the control circuiting for the shift effecting means independent of the ignition interruption control circuiting during upshifting.

A further object is to provide a transmission control system including ignition interrupting means and speed responsive and/or accelerator controlled differential pressure fluid means for effecting speed changes in the transmission wherein differential pressure fluid responsive means is provided in series with the interrupting means to protect the ignition system against weakening of the ignition spark intensity when the interrupting means is operated during upshifting.

Another object of my invention is to provide a transmission control system including ignition interrupting means and differential pressure fluid means for effecting speed changes in the transmission wherein the ignition interrupting means is operable to effect a change in the condition of the ignition system only at or above a predetermined fluid pressure.

Other objects and features of my invention will be apparent from the following description wherein:

Figure l is a diagrammatic plan view of the driving power plant for the vehicle;

Figure 2 is an elevational view partly in section of my invention as applied to a semi-automatic four speed forward and reverse transmission, a part of the control system being schematically illustrated, the manually operable clutch sleeve being shown in its forward or high range position for starting the vehicle from rest, and the power shiftable mechanism and power operable clutch sleeve being shown in the released position of the latter; and

Figure 3 is an elevational View similar to a portion of that in Figure 2 and showing the power shiftable clutch sleeve in its direct drive or en- Agagedpositien and the power shifting mechanism'in the correspond-ing position.

In the drawings in which similar numerals indicate similar parts of the structure, Figure 1 illustrates a typical motor vehicle power plant having a conventional engine A for transmitting power through a propeller shaft Hl to drive the rear ground wheels II. n the housing B there may be provided a fluid power transmitting device, such as a fluid coupling arranged in tandem with a master friction clutch of known type, the latter being releasable to uncouple the engine from the transmission by operation of a conventional clutch pedal I2. Rearwardly of the housing B is a transmission C which may be of any type incorporating positively engageable drive control elements of a character usually subject to substantial thrust or torque load in operation, the latter conditions making the use of some form of unloading means desirable to insure release of the drive control elem-ents when a speed change requiring disengagement of these elements is necessary.

The transmission C may be of various known types. For purposes of illustration I have shown in Figure 2, a commercial form of four-speed and reverse countershaft underdrive transmission. This transmission comprises an input or driving shaft I3 which receives drive from the engine A by way of the clutch assembly B, and an output or driven shaft I4 which is adapted to transmit drive to the propeller shaft I0. The driving shaft I3 carries the main driving gear or pinion I5 and a set of positive jaw clutch teeth I6 which are adapted to be engaged by the teeth of a jaw clutch sleeve D. As will be hereinafter seen, the sleeve D together with the clutch teeth IScomprise relatively movable drive control elements for effecting stepup and stepdown manipulation of the transmission.

The clutch sleeve D is slidably splined on teeth, not shown, of a forward hub portion of the high or third speed gear 22 which is rotatably joui'- nalled on the driven shaft I4 and adapted to be clutched `thereto through a jaw clutch sleeve F slidably splined on a hub, not shown, drivingly carried by the shaft I4 and interengageable with jaw clutch teeth 25 carried by the gear 22. The forward shift of sleeve D for clutching with teeth I 6 is normally controlled or impeded by a toothed blocker E` wherebyclutching is 'limited to synchronous relationship in the speeds of rotation of gears I5 and 22 and, in the particular construction illustrated, limited to engine coast conditions obtainable by accelerator releasing movement to secure receleration of the engine. The blocker E is journalled on a conical surface, not shown, carried by the shaft I3 against which it is lfrictionally urged by a spring, also not shown, and has a limited lost motion connection with the sleeve D or gear 22 whereby it may rotate to place its teeth in blocking relation to the teeth of sleeve D whenever the gear I5 rotatably leads or lags the sleeve D. VWhen sleeve D moves past the blocker E into engagement with the clutch teeth I-B, the gears I5 and 22 are placed in a two-way direct drive relationship.

s Gear 22, as stated'above, is loosely journalled on the driven shaft I4 whereas the pinion I5 is part of the input shaft I3. Also loosely journalled on the output shaft I4 is a low or rst speed gear 21 having jaw clutch teeth 28 engageable by the sleeve F. Associated with the sleeve F on each side thereof is any commercial type of blocker synchronizers 29 such that clutch F may be shifted from a neutral position Vdisengaged from teeth 26 and 28 forwardly to a high range position to synchronously clutch shaft I4 with the high speed gear `22 through theA vteeth 26 Aorrearwardly Ato a-low range position to synchronouslyclutch shaft I4 with-the'low speed gear l21 lat its teeth 28.. Manual shiftso'f :the sleeve F arefacilitated by release'of the main clutch at B by means of the clutch pedall2.

Gear 22 is also adapted to be driven from.l gear Izat a speed differentfrom 1:1.and-to this end Lhave shown a countershaft type vone-way reduction driving means betweenthese gears. This drive n'comprises the coaxially rotatable Y countershaftqgear .30 and clusterfgear3l, .wheels-132,33 respectively, in constant mesh with'gearsl, 22, and 21 and an overrunning roller clutchG operablyinterposed therein-between theigear '.30 vand clusterI. Astationarily mounted countershaft 341iprovides :a `journal. support for the countershaftgears. .Assuming theusual clockwise rotationof shaft I3 as viewed whenlooking from front to rearof Figure 2, then overrunning clutch G will automatically VVclutch geari) and cluster 3I' together when gear 33 is. driven counterclookwiseat aspeedtending to exceed that ofthe cluster 3I andautomatically release the Vdrive between these gears to allow gear 3S) ,to-slow down vbelow the speed of cluster 3l. For obtaininglreversedrive .anidler gear (not shown) having constant mesh with the gear 33 is shiftable rearwardly intoimesh with a gear 35 fixed on shaft I4, `the clutch 'F ibeing then in its neutral positiondisengaged from teeth .26 and 28.

.Asxthus far described, it will be apparent that withrthe ,parts .arranged as in Figure 2,-sleeve. F Vbeing then in high range position engaged with teeth'26, drive .of shaft I3 will cause theioutput shaft I4.to be driven at a reduction drive (third speed) .through the gears I5, 30, overrunning clutchV gears 32, 22 and sleeve F. Shouldthe sleeve Dbe :biased forwardly during this reduction drive, blockerE willobstruct sleeve Din an intermediate position of. its shift preventingv ratcheting of its teeth with the :teeth IS. However, ifthe driver releases theengine throttle control in the form of the usual acceleratorpedal then, as will, be apparent, 'overrunning clutch Gr will/allow .gear I5 andteeth ltoslow down relativeto thesustained speed of Ygear 22 and when 'the speed of gear..|5 .reaches synchronism withthatof gear 22,.;blockerV E willmove to an unblocking'po'sition and allow sleeve D to move further forwardlyzto clutch its'teeth with'teethlto the position showninFigure 3, to provide thevdirect drive (fourthispeed), clutch G continuing its overrunning operation. Upon return of sleeve D to disengaged positionshown in Figure 2, followed by speeding up the engine, overrunning clutch G will automatically engage to lrestore the vreduction drive.

When clutch sleeve 'Fi is shifted'rearwardly to low y'range `position to clutch gear 21 to shaft I4 an-overrunning `slow speed drive, v(first speed) is transmitted from the shaft I3 to the shaftv I4 by way of the gears I5, 30, overrunning clutch G, gears'33 and 21 and sleeve F. At such time as the sleeveD is biased forwardly and the shaft I3 is allowed to slow down to permit the teeth I6`to^become synchronized with the sleeve D, the sleevewill move past the blocker E and clutch withthe teeth I6 to establish a two-way relatively fast speed drive (second speed) in the low range, which drive will be fromthe shaft I3 through the :sleeve D, gears 22 and 32, gears 33,-and 21, andclutchF tothe shaft I4, the clutch Groverrunning byreason of thecluster 3i rotating 4at a-higherffspeediforwardly than the gear 3B.

It-willl be understood fthe .driver maystart the vehicle from rest in the low range: drive andfsub-4 sequently shiftfto the high range incident to momentary release ofthe master .clutch andithis either prior .to or subsequent to engagement of the clutch D. Most drivers, however, .usually starty the vehiclefrom rest in the Yslow speed ratio of "the high range and at a subsequentv higher speed obtain` the automatic .upshift vto direct drive by 'momentary release of the accelerator pedal `described above.

`A'morefcomplete description of the transmissionfspecically illustrated in this application and its method of operationis set forth in thepatent to JA. .I. Syrovy etal. 2,490,604 aforesaid.

A speed responsivegovernor means O is provided to ycontrol forward bias of the sleeve Das wellfas rearward bias-thereof as will be presently `more apparent. Moreover, during drive lin either second or fourth speeds referred to above, a-downshift to first or third speeds respectively may be effectedby way of overruling the governor'O'through driver depression of the accelerator pedal'Mtosubstantially wide open throttle position, which operation is referred to in greater detail below.

As-seen in-Figure 2, I have illustra-ted a-'servo motor H by which t-oobtainfpower actuationof the'clutc'h sleeve D, the motor here illustrated being of the pressure diiferentialV and spring opel'- atecl typel and in the disclosed embodiment functioning'bymeans of uid pressure. This motor preferably comprises a cylinder 36 slidably receiving .a piston-31. The piston slidabli7 receives ashiftrail or rod 38 mounted to operate in the gudeways 33 and-4Q. VFixed t0 rod Sis a yoke 4I, a hub portion cl2-of which is secured to the rodSS by means of a dowel screwl 43. Therod 38 and :yoke 4I constitute motion transmitting means S for 'the sleeve D, the yoke 4I as seen-in Figure V2, having fingersv 44 engaging in a groove 45 of the sleeve D to effect shift thereof.

.A relatively small preloadedengaging spring 46 surrounds therod 38 Yand is disposed between thexhub of` piston 31A and the hub 42 of the'yoke 4I. Thisuspring 43 provides a lost motion thrust ltransmitting.connection between the piston 31 and'thefhub 42=Of the motion transmitting means S such that .the-piston 311 may be moved forwardly (to the left in Figure 2) for its power stroke, the pistonl31 continuingits forward motion by fiuid .pressure even after Ythe clutch D hasbeen moved againstthe blocker E until the lip 41 of the piston uncovers the relief port @S of the cylinder 3G whereupon forward movement of the piston 31 will cease, the fluid pressure being then expended through'the relief port e3.

. During. the. said forward movement of the piston 31 the engaging spring 45 is compresed and urges the: rail 38 through the hub e2 of the-yoke 4I forwardly thus in turn shifting the clutch sleeve Dato itsr intermediate position blocked by -theblocker E. Subsequently upon synchronous rotation of the teeth I6 and sleeve D being obtained in response to accelerator releasing-movement, the sleeve D is moved through the blocker E into engagement withthe teeth I6 of the drive pinion I5, which is its vfully engaged upshifted position shown in Figure. 3, establishing the previously described direct drive between the shaft I3 andgear 22.

A. relatively largepreloaded downshift orkickdown spring 49 is disposed betweenanabutment ringV 50, located at 4the forward end of the cylinder 36, andthe piston 31. This spring serves to return the pistonV 31 and sleeve D from their Figure 3 positions to their downwshiited or disengaged position shownv in Figure 2. It will be observed from Figure 3 that the piston 31 when in its furthest forward position shown in this figure uncovering the port 48 has moved further than the shift rail 3S such that aV gap 5| is created between the piston 31" and a shoulder 52 of the portion Y53 of theshift rail. This gap 5| facilitates a lost motion movement of the piston 31 relative to the shift rail 38 prior to disengaging movement of the sleeve D which can only commence following abutment of the piston 31 with the shoulder 52. As previously noted, forward movement of the piston 31 is stopped upon uncovering the port 58, the latter permitting any excess pressure required to hold the piston 31 in its furthest position to be relieved and preventing the building up ofsuch excess pressure in the cylinder.

A pressure of between 38 to 40 p. s. i. in the cylinder 36 will move and hold the piston 31 in its furthest forward position against the resistance of springs d'6 and Q3. Below this' pressure the springs will return the piston to the Figure 2 position.

'Ihe pressure iluid supply system is shown in Figure 2 and comprises a suitable supply source 6U, which is usually the transmission sump. A pump Q of the rotary gear type is mounted on the shaft |fi and has its rotor 6l driven by that shaft, oil being drawn from the supply source 60 through the conduit 62 to the pump inlet 63 and is delivered under pressure at the pump outlet 64 to the conduit 65 and then to the passage 66 under control of a yball valve K. A relief valve, generally designated by the numeral 61 and proy vided at the pressure side of the pump between the outlet 64 and the ball valve K serves as a relief valve in the event the valve K is not open in normal operation of the transmission to thereby permit pressure uid trapped behind the piston 31 to be dumped back into the transmission sump 66 through the conduit 61a.

When the valve K is closed, oil under pressure is forced directly from the pump through the passage 66 to the cylinder 36 where i-t moves the piston 31 forwardly to effect forward movement of the shift rail 38 in the manner described above whereby the shift sleeve D is operated from its Ydisengaged position in Figure 2 to its engaged position of Figure 8 to establish second or fourth speed ratio drive depending upon whether the clutch F is engaged with the first speed gear 21 or with therthird speed gear 22.

Valve K is closed by bias of a valve spring 68 acting against a lball 69 to close a discharge port I opening into a passage 1| draining to .the sump or supply source 69. The valve K is actuated to its open position under control of an electromagnetic device `comprising a solenoid L having a plunger 12 connected with the movable core of the solenoid. The valve K is closed when the solenoid L is deenergized. The spring 68 then actuates the ball 69 against a seat 13 to close the port 16 and effects movement of the solenoid plunger 12 to its retracted position, The valve K is open when the solenoid L is energized, the solenoid core then moving the plunger 12 downwardly to push the ball 69 off the seat 13 of port 16. The oil may now flow from the pump Q through the conduit 65, port 16, passage 1|, back to the sump 66.

When the valve K is open, Yit is impossible for' suflcient uid pressure to develop in the passage 66 to move the piston 31 against the force exerted by the piston return spring 49 which then maintains the piston at the extreme rearward position of its capable movement. Hence the piston 31 is actuated by fluid pressure only to establish second and fourth speeds respectively at which time the valve K is closed and the solenoid L deenergized. Figure 2 shows the valve K in its open position and the piston 31 in its position retracted by spring 49, and Figure 3 shows the valve K in its closed position and the piston 31 in its furthest forward position .under control of the pressure uid.

Energization and deenergization of the solenoid L is brought about by operation from one position to another of either of two control members, one actuated in response to vehicle speed, and the other in response to manipulation by a driver control member One ofv these control members is the governor O, and the other is a kickdown switch generally designated by the letter P. Suitable electrical circuit means are provided for effectuating the control operation of the governor and kickdown switch over the solenoid L. Thus a suitable source of electrical energy, for example, a storage battery 15 has one side grounded as at 16 by a conductor 11 and its other side connected by a conductor 18 through an ammeter 19 to the ignition switch 8D. A conductor 8| connects the ignition switch with one terminal 82 of the solenoid L, the other terminal 83 of the solenoid being connected by a conductor 84 with a terminal 85 of a switch generally designated by the letter N which is operated by the governor O and which .has a second terminal 81 connected to a ground 88 by a conductor 89. From the governor switch terminal 85 a conductor 99 extends to a terminal 9| of the kickdown snap switch P, this switch having a second terminal 92 connected to a ground 93 by a conductor 94.

The governor switch N is closed by ar movable conductor switch bar 95 operated by an insulated sliding sleeve 96 of the governor O, the switch being closed when the bar 95 bridges the terminals S5 and 81. 'I'he kickdown switch P is of the snap type and has a conductor bar 91 which closes the same by bridging the terminals 9| and 52 of this switch.

Thus by means ofthe governor switch N and the kickdown switch P, two parallel ground circuits are provided for the solenoid L, the governor switch N opening at a speed proportional to vehicle speed established by the drive connection |60, l between the governor O and the countershaft cluster 3|. It will be understood that the governor driving means Il, may if desired be on the driven shaft I4.

The kickdown switch P, as shown in Figure 2, is in open position under control of a coil spring |32 and which biases the accelerator M to its released position.

The accelerator M is suitably connected with the usual engine carburetor throttle valve by means including linkage |03, |64 which serves to open and close the throttle valve. Interposed in the throttle valve operating linkage isa lever 65 pivotally supported at |06 and having spaced ngers or projections |68, H6 for operating the actuating finger ||2 of the snap switch P. The mechanism is preferably arranged such that in operation, the switch finger ||2 is engaged by the leverprojection |08 as the throttle valve in 85 of :the switch N response :to depression :of the accelerator M; a-pproaches itsfull open throttle.` position; ,so that the switch Pis. closed with snap' action. during approximately the last or lso of throttle-opening movement. It will be understood that the operation o1" this switch maybe adjusted to occur subsequent to full open throttle position bythe provision of suitable lost motion mechanism such as disclosed in the patent to Neracher et al. 2,455,943. When the raccelerator M is released, the' ngerl |0 comes into contact with the vactuating'nger H2 of theswitchnear the fully releasedV position of the accelerator toactuate the rswitch P toits open position, again by snap action,.the parts being so arranged that the switch P will be'openedby nger HG whenever the acceleratorpedalfis fully released.`

Theignition mechanism generally designated by'theletter J is oi' conventional type cludes an ignition coil |20, a distributor |22, and; a' breaker |24. From the'primary coil |25 an ignitiongrounding circuit is provided that-extends through the condaictors |21, |28, |29: to terminalv |39 of a normally'l open interrupter switchTVan-d tlfienoeiromv terminal |3|jthere of bylthe. conductors |32', llltoithe ground .88 provided bythegovernor switch :N or bythe .conductors:|S2,|3and.||| .to the ground'iS'of the kickdown. switch P.

As noted above, prior control circuits and structures'providing the valve solenoid and ignition: primary coilin parallel arranged circuits made: it possible for the solenoid to function as parallel. impedancefof lowvalue to the primaryfcoil and weakenftheispark delivered by the secondary at the spark-,plugs |35when current iiow'thereto took place.

A eature'o the'present invention is to overcome this difficulty and'v to accomplish this I providev in .ther series circuit between' they circuit breakeri-Z o the ignition and the-solenoid L and in series with theignition interrupting switch, a'further'control switch Y which I may term, for convenience, an impedance control switch.y This switch will preferably be operated to permit ignition interruption during a governorA or accelerator controlled downshit, but will prevent a circuit being established between the solenoid L and thev breaker points |36 .during upshifting. Stated otherwise, the switch Yvwill be closed only whenthe dierential fluid pressure condition in thefmotor E is such as to enable the spring if? to'urge the piston itoward or maintain. it in itsdownshifted position of Figure 2.

orderto avoid hunting oi the solenoid L dow-nshiting, it is. essential to place the switchr in the circuit between the breaker contacts the common terminal 850i the governor switch N and kickdown switch P.

Inthe disclosed embodiment of the invention, I have providedthe sv 'tch Y in the form of a pressure responsive switch connected between the ignition interrupting switch Tand the terminal, tiet the governor switch N, the conductor IBZleadingy from the terminal |3| of .the switch 'I to the terminal |3|lof .the pressure switch vY andthe conductor |34 connecting the terminal with the terminal |65) of the pressure switch Y.

Theswitch Y comprises a base Isl of insulated material seated ona wall portion H52 ofthe transmission casing and mountingthe-terminals |38; Mi! in spaced relation, anda switch closing member orbar |43rnorrnally held bya spring'lM y in a position to close this switch by bridgingfthe and ininnerextensions ofthe-terminals |38, Milf. A passage.v member |||`v places the :switch member |42 under the'iniiuerloeoi fluid pressure by connecting the switch with the fluid passage 66;

In the disclosed embodiment the switch will close when the fluid pressure Vinthe passagel E6 drops to or ybelow a predetermined value, for eX- ample 30 p, s. i., but'will open when4 the fluid pressure reaches orexceeds a higher. predetermined value, foreXample-SSp. s; i. Hence the switch YV will be open at-all times that the sleeve D'is engaged, willclose when the motor I-I is vented,` and willopen lagain when pressure sufcient to effect actuation of the piston'31 to engage thesleeve -D isadmitted to the passage Sii by the valve K.

It will be noted that the piston 31 has'its outer skirt |60'reduced at |6-I adjacent the cammed portions |62, |63 for controlling operation of the ignition interrupter switch T of known type. Thisswitch is ybiased toppen position by a spring it-and has its operating 'stem engaging 'a ball |56 sor arranged'inassociation with the 'piston portion |60 that switch T is open'when the piston is-in the Figure 2 position and in the Figure -3 position ofV forward movementv ofV the piston. However, as the-cammed portions m2; |53' move by the'ball li'in-either direction of movement of the piston, the ball |66 is actuated to close the switch T. Thus in theforward -movement of the piston the cammed yportion I 62 operates the ball and the cammed portion |63 permits theball to return to open position of the switch by dropping in the reduced portionxl 6| ofthe piston, the ball being shown in thisposition in' Figure 3. On 'the downshifting'movement of 'the piston, the cammedportion |63 actuatesrtheiball-'Itto close the switch T and the cammed'portion |52 rpermits theball to return tothe open position of the switch T.

The operation of the transmissionand control system will now described. Letit` be lassumed that" the vehicle is' at a standstill with the manual sleeve F shifted forwardly inengagement with the-teeth26 of 'thethird speed gear 22, as seen in Figure 2. At this time thegovernor switch Nwill befclosed and providesa circuit from--the-battery l5 to the ground "86 by wayv of the conductors 13, 8| and thesolenoid'L, thus energizing the latter whereby the solenoid rod 12 maintainsthe ball -69 of the valve'K- in its down position'venting the motor H so that the spring 'holds the pistonv 31 and the clutch' sleeve -D -in theposition shown in this figure. The ignition interrupter switch T is open as shown, the ball operator |66 tthereofbeing free of` the skirt l of the piston 3l. The control switchl Y- is closed since thefluid pressure yin the passage 65 is below pumpV pressure, or'. statedotherwise, below i0n lbs. per square inch. The kickdown switch Pis'openy since the acceleratorfpedal is'released.

Bydepressing the accelerator Ypedal-within its normal operating range, the vehicle isdriven in third speedratio drive. Atv some predetermined speed of vehicle travel, for example 12 to 14 M; P; H; (6 to 7 M. P. H. in rst speed), the governorJO .actuates the switch N to' open position thusv breaking thecircuit between the ground 8% and the conductor lill.` The solenoid L is thereuponfdeenergized and the valve K closed by operationofthe spring 68 which moves theV ball til-of .the valve to close the port 1|) at the entrance ofthe return passage 1|, thus lpermitting pressuregto Abeb'uilt upby the pumpQ in the passage At the moment of operation of the solenoid L, the interrupte'r switch T is in open position and the control switch Y is in closed position, the parts being thus shown in Figure 2. When the fluid pressure in the passage 66 builds up sufiiciently, the piston 31 moves forwardly for its upshift stroke and comes to rest at the position shown in Figure 3 where the relief port 48 is uncovered by the piston to relieve fluid pressure in excess of that required to maintain the piston at this position. The uid pressure utilized to move the piston 31 from its Figure 2 position is also sumcient to actuate the member |43 of the control switch Y to break the circuit across the contacts |38,V |40 of this switch establishing the switch in open position.

During forward movement of the piston 31, the springs 46 and 49 are compressed. Initially the spring 46 moves the motion transmitting means S and thereby the sleeve D to its blocked position against the blocker E. Then lost motion takes place between the piston 31 and the shift rail 38 during which the springs 46 and 46 continue to compress. During the lost motion movement, the skirt |60 has its cammed portion |62 move past the ball |66 of the switch T camming the ball |66 upwardly to close the switch T, vthe switch T remaining closed until the cammed portion |63 of the skirt |60 passes under the ball |66 at which time the ball drops into the recess or relief portion |6| of ther piston to re-establish the switch T in open position. Thereafter, upon accelerator release to synchronize the speeds of the sleeve D and the clutch teeth I6, the sleeve D is moved by the spring 46 acting upon the yoke 4| of the motion transmitting means S, to its engaged position shown in Figure 3. During this engaging movement, the rail 3B moves forwardly relative to the piston 31, the latter remaining in its position shown in Figure 3, uncovering the port 48.

Although the switch T is operated during the forward movement of the piston 31, the spark delivered by the secondary coil of the ignition system at the plug |35 is neither interrupted nor weakened for the reason that the circuiting between the solenoid L and the breaker points |36 is maintained open by the control switch Y which had been previously opened upon admission of fluid pressure into the passage 66. ground is available for interrupting the ignition system, nor is it possible for the solenoid L and primary coil |26 to be simultaneously subjected to current flow in parallel circuits having as a common ground terminus the breaker points |36.

Once established in fourth speed, a downshift to third speed is eiected either by manually closing the kickdown switch P by means of the accelerator pedal M or by the automatic closing of the governor switch N when the speed of the vehicle drops below the upshift speed set for the transmission. For example, when the driver desires to manually effect the downshift from fourth speed to third speed, he fully depresses the accelerator M. During this operation, for example. as the throttle approaches its full open position, the switch P is closed. Since the engine is then delivering its full power, it is desirable to eiect torque relief at the teeth I6 to facilitate the release of sleeve D for the downshift. At this time the switch T is in its Figure 3 open position with the ball |66 in the recess |6| of the piston which is then in its position adjacent the relief port 48. Moreover, the motion transmitting means S' is in the fully engaged position of the sleeve D as shown in Figure 3, and the control switch Y is in its Figure 3 open position. Closing of the switch P applies the ground 93 to the solenoid L circuit from the battery 15 causing energization of the solenoid L and opening of the valve K to vent the motor H. Opening of the port 10 of the valve K by the solenoid L permits the pressure in the passage 66 to drop rapidly causing the switch Y to immediately return to its closed position under bias of the spring |44 and permitting the piston 31 to commence its rearward movement under bias of the spring 40.

As noted above, the ignition interrupting switch T, which connects by the conductors |21, |28, |23 with the primary Winding |26 of the ignition coil |20, is in series with the control switch Y and the ground 93 established by the kickdown switch P through the conductors |32, |34, and 64. Moreover, it was observed above that when pressure is vented in the cylinder 36 of the motor H, the clutch sleeve D usually initially remains engaged while the piston 31 begins its return movement under urging of the spring 49, by reason of the engine torque on its teeth. Hence the piston 31 will initially take up the lost motion movement 5| between itself and the shoulder 52 of the end portion 53 of the rail 38. During this lost motion movement the cammed portion |63 of the piston moves under the ball |66 of the switch T thereby urging the ball |66 upwardly to close the switch T and complete the circuit between the primary winding |26 and the ground 93 of the kickdown switch P thereby grounding the ignition system. The engine now missing fire, unloads the torque on the teeth of the sleeve D thereby permitting the spring 49 to effect disengagement of the sleeve D by moving the piston 31 and rail 38 further rearwardly and complete the rearward or return movement of the sleeve D, piston 31 and rail 38 to the position shown in Figure 2. During this return movement the cammed portion 62 of the piston passes under the ball |66 of the switch T permitting the switch to returnrto its open position restoring the ignition to normal operation. When subsequently the accelerator pedal M is released suii'- ciently to open the switch P, fourth speed ratio drive may again be restored as previously described provided the vehicle speed is still such that the governor switch N is open.

For the automatic downshift from fourth speed to third speed under control of the vehicle governor O, it is only necessary to reduce the vehicle speed to or below the speed at which the governor switch N normally closes. Closing of the switch N energizes the solenoid L by eifecting a circuit from the battery 15 to the ground 88. The motor H is then vented and switch Y closed, as described above with respect to the kickdown operation of the transmission and the interrupter switch T is operated as there described.

When the sleeve F is in its rearward or low range position, then upshift and downshift movement of the sleeve D between rst and second speed positions will be the same as that set forth for the operation of this sleeve between third and fourth speed positions when the sleeve F is in its high range setting. However, since the governor O is driven from the countershaft as at |00, |0| in Figure 2, the governor O will function at a somewhatlower car speed depending upon the gear ratios for iirst and second speed as compared with third and fourth speed as will be readily understood. It will be noted, however.

Vtlflat-tlle governorl driving means sired, be on Ithe driven structure .for transmissions relative toY another second position of engagement .terrupting switch means andy breaker points, ground applyingswitch lmeans 'apagado mi! may-,ifdeshaft |4.-

From the foregoing description of'lmyfinven'- tion ity willbe apparent that Ihaveprovidedl a novel 'ignition interruptor havingv both governor and'lmanuallycontrolled downshifting wherein ignition. interruptiony for disengagingr engaged clutch-elements is obtained as required,.andop eration v'of the interruptor means during upshiftingV operations will .not cause. any weakening of the spark. delivered bythe secondary winding of the. ignitioncoil at. the plugs .at the time of current flow thereto.

It 'will' also be apparent that the invention is applicable to other forms of transmissions. Moreover, although' the .disclosed embodimentof the .inventionis well `adapted .iorcarrying out the obje'cts..hereinaboye set forth, it will be. understoodthat various modifications, changes.` and substitutions coming within'thespirit of my '1invention and within the scope oi the appended claims .are also contemplated.

claim:

l. In a power transmission for driving `a `Vehicie having an engine .provided with'an ignition sytem; va shiftable transmission drive control element shiftable' from a iirst position disengaged drive control element to a element and shiftable out of said second position when-operation tof said ignition system is momen'- tarilyi interruptedv to 'relievethe thrust load at said shiftableelement, means foreectingshiit of said shiftable drivecontrol elementhetween its f twosaid positions, electromagnetically loperable means for controlling-saidlshiit effecting means, ignition interrupting switch meansoperab-le vby said shi-iteecting 'means when eiecting-.shit or said shiftable drive -controlelement between said nrst and -secondpositions and again betweenfsaid Vsecond and rlrst positions, ground applying switch v means in serieseloctrical-ly with:r said electromagnetioally operable means, and` a control switch in series-electrically withsaid ignition vinwith said. ground applying switch means.

2.v Inla kpower transmissionor. drivingr a Vvehicle having an engine provided withr an ignitionY system including a .primary ignition winding and Breaker contacts electrically in series, a shiftab'l'e. transmission rdrive control element' shiftable. irom `a rst position disengagedv relative to another drive control element' to a second position of engagement with saidLotlierY elem'ontrand shirtable outof. said second'pp'sition when/operation of said'ignition' system is momentarilyinterrupted toirelieve' the thrust loadat'said shiftable` element; meansy fore'eiecting Vshift or said shiftable drivecontrol element between its two saidV positions, Y* lectromagnetically operable means 4for controlling said shift effecting moans, ignition'l'intorrupti-ng switch means electrically in series with each ofi said primary w'nding. and in series electrically with said .electromagnetically operable means,. and a control :switch .electrically intermediate said' ignition' interrupting switch means andy saidground applying switch means.

3. n apower transmission for drivingt'a-vehicie having an engine provided with-.an ignitionl system including a primaryignitionY winding and breaker contacts electrically in Serieaashi-table transmission drive control .element shit-table -from a rst Vposi-tion disengaged relative to another drive control element to a second position of control system andr with said other said positions,

Viirst positions; ground applying vable for controllingv said engagement with said Lotherelement `and'l shifta-hleout-of said second'- posi'tion. when 4operation of said ignition system is momentarily linter- -riipted to relievethe 'thrust load at said-shift- 'ableelement, means for effecting shift :ofi said shif-tahle -drive ycon-trol element-between 4its two electromagnetically voperable `means1-for`A controlling said shift effecting means, ignition'interrupting` switch means having an 'openI andi a .f closed position and momentarily :operahl'eiby said shift .effecting means tovclosed position-when effecting shift of said s'hiitable drive-'control element 'between said rst and second? positionsand again between said second fand switch means in series-f electrically withy said electromagnetically operable'means, anda Vcontrol switch having'an open and al1 closed position,said controlswitchbeing-.arranged electrically intermediate said lignitioninterrupting switch means and saidground applying means and saidcontrol switch being operable to open position substantially when initiating shift fof-"said shiftable drive control element'rfromsaidnrst to'said second positions.

4. apower transmission for driving a vehiclehaving an engine provided with an ignition system; -a shiitable transmission drive control element shiftable froma first position disengaged relative 'to 'another drive control element to a secondposition` of engagement with said other element and shiftable out of said second-position when'operationof'said' ignition system is momentarilyY interrupted to relieve the-thrust load at said shi-ftable element, motion transmitting means for shift-ing' said sh-iftable drive lcontrol element, actuating means operable `upon said motion transmitting means vfor eiecting shift of saidrshiftable drive control element between its twosaid positions, electromagnetic means operactuating means, gover-nor'means for controlling operation of vsaid electromagnetic means, ignition 'interruption switch means operable by said actuating means, andpressureresponsive switch means vfor preventing vweakening of the ignition during engaging'shiit ofsaid-shiftable drive control element.

5; In -a power' transmission for driving a vehiole *havingan engineprovided with an ignition system including a primary winding; a -shiftable transmission `drive `control element vshiitable from a first position 'disengaged relative to another drive 'control element to a rsecond position of engagement with said other element and shiftable out 'of said Asecond position when operation of saidignition' system is momentarily interrupted torelieve `the thrust load at said shift- 'able element. motion transmitting means for lshifting said shiftablo rdrive control elementac tuatingmeans operable uponl said motion transmitting means for eiecting shift of said shiftable drive: control element between `its two said positions', electromagnetic means operable .for controlling saidv actuatingv means, governor means for-'controlling operation of said electromagnetic means, driver'operabl'e means for controlling operation Aof vsaid electromagnetic means, ignition 'interrupting means and ignition interrupting control' means, said last .two mentioned means heing electrically inseries witheach of said governor means, said ydriver operable control means hicle having an engine provided with an ignition system including a primary ignition winding and breaker contacts electrically in series, a shiftable transmission drive control element shiftable from a first position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, differential pressure fluid operable means for effecting shift of said shiftable drive control element between its two said positions, a valve for controlling said shift eifecting means, a solenoid for controlling said valve, ignition interrupting switch means electrically in series with each of said primary winding and breaker points, ground applying switch means in series electrically with said solenoid, and differential pressure operable control switch means electrically intermediate said ignition interrupting switch means and said ground applying switch means and in series electrically with each thereof.

8. In a power transmission for driving a vehicle having an engine provided with an ignition system including a primary ignition winding and breaker contacts electrically in series, a shiftable transmission drive control element shiftable from a first position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, differential pressure iluid operable means for effecting shift of said shiftable drive control element between its two said positions, a valve for controlling said shift effecting means, a solenoid for controlling said valve, ignition interrupting switch means electrically in series with each of said primary winding and breaker points, speed responsive ground applying switch means in series electrically with said solenoid, and differential pressure operable control switch means electrically intermediate said ignition interrupting switch means and said ground applying switch means and in series electrically with each thereof.

9. In a power transmission for driving a vehicle having an engine provided with an ignition system including a contacts electrically in series, a shiftable transmission drive control element shiftable from a hrst position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, differential pressure fluid operable means for effecting shift of said shiftable drive control element between its two said positions, a valve for controlling said shift effecting means, a solenoid for controlling said valve, ignition interrupting switch means electrically in series with each of said primary winding and breaker points, speed responsive ground applying switch means in series electrically with said solenoid, operator-operable ground applying switch meansin parallel electrically with said speed responsive switch means, and differential pressure operable control switch means electrically intermediate said ignition interrupting switch means and said ground applying switch means and in series electrically with each thereof.

10. In a power transmission for driving a vehicle primary ignition winding and breaker having an engine provided with an ignition system including a primary ignition winding and breaker'v contacts electrically in series, a shiftable transmission drive control element shiftable from a irst position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said shiftable drive control element, dilferential pressure operable motor means including a piston, operable upon said motion transmitting means for eifecting shift of said shiftable drive control element between its two said positions b-y said motion transmitting means, electromagnetically operable means for controlling said shift effecting means, ignition interrupting switch means having an open and a closed position, and momentarily operable by said piston to closed position when effecting shift of said shiftable drive control element between said first and second positions and again between said second and rst positions, ground applying switch means in series electrically with said electromagnetically operable means, and a control switch having an open and a closed position, said control switch being arranged electrically intermediate said ignition interrupting switch means and said ground applying means and in series electrically with each thereof and said control switch being operable to open position substantially when initiating shift of said shiftable drive control element from said rst to said second positions.

ll. In a power ltransmission for driving a vehlcle having an engine provided with an ignition system including a primary ignition winding and breaker contacts electrically in series, a shiftable transmission drive control element shiftable from a rst position disengaged relative to another drive control element to a second position of engagement with said other element and shiftable out of said second position when operation of said ignition system is momentarily interrupted to relieve the thrust load at said shiftable element, motion transmitting means for shifting said -shiftable drive control element, diierential pressure operable motor means including a piston, operable upon said motion transmitting means for effecting shift of Vsaid shiftable drive control element between its two said positions by said motion transmitting means, a, valve for controlling said shift effecting means, aY solenoid for controlling said valve, ignition interrupting switch means electrically in series with each said primary winding and breaker points, said interrupting switch means having an open and a closed position and being momentarily operable by said piston to closed Iposition when effecting shift of said shiftable drive control element between said first and sec-ond positions and again between said second and iirst positions, speed responsive ground applying switch means in series electrically with said solenoid, -driver operable ground applying switch means in parallel electrically with said speed responsive switch means, and vdifferential ipressure fluid operable control switch means having an open and a closed position, said differential pressure switch means being yarranged electrically intermediate said ignition interrupting switch means and said ground applying means, and in series electrically with each thereof, yand said differential pressure switch 17 means being operable to open position substantially when initiating shift of said shiftable drive control element from said first to said second position.

12. In a power transmission for driving a vehicle having an engine provided with an ignition system including a primary ignition winding and breaker contacts electrically in series, a shiftable transmission drive control element shiftable from a first position disengaged relative to another drive control element to -a second position of engagement with said other element and shifta'ole out of said second -position when operation of said ignition system is momentarily interrupted to relieve the thrust load 'at said shiftable element, motion transmitting means for shifting said shift-able drive control element, differential pressure operable motor means including a piston, operable upon said motion transmitting means at a predetermined differential fluid pressure for effecting shift of said shiftable drive control element between its said first and second positions and operable at a different predetermined differential fluid -pressure for effecting shift of said shiftable drive control element from its said second position to its said first position, a valve for controlling said shift effecting means, a solenoid for controlling said valve, ignition interrupting switch means electric-ally in series with each said primary winding and rupting switch means having an open and a closed breaker points, said intero 'l position and 18 being momentarily operable by said piston to closed position when effecting shift of said shiftable drive control element between said first and second positions and again between said second and rst positions, speed responsive ground applying switch means in series electrically with said solenoid, operator-operable ground applying switch means in parallel electrically with said speed responsive switch means, and differential pressure fluid operable control switch means having an open and a closed position, said differential pressure switch means being operable to said open position upon establishment of said first mentioned differential fluid pressure in said motor means and to closed position upon establishment of said different differential pressure in said motor means, and said differential pressure switch means being arranged electrically intermediate said ignition interrupting switch means and said ground applying means, and in series electrically with each thereof.

LOUIS B. FORMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,440,055 Matulaitis Apr. 20, 1948 2,509,981 McKecknie et al. May 30, 1950 

